Linking Environmental and Economic Sustainability in Beef Feedlot Production
Environmental sustainability is a major focus for most industries. Agriculture in general, and beef production in particular, are clearly tasked with achieving improved environmental sustainability. The handicap to beef has been that all methods introduced to reduce greenhouse gas emission by beef cattle to date result in production costs being greater than any related economic benefit. As a result, efforts to reduce greenhouse gas emissions in beef production have not been economically sustainable or widely adopted.
Beef cattle are ruminants, which means they depend on microbial fermentation in their digestive system to convert the feed they eat into nutrients they can use to make meat and milk. This makes them important to human nutrition because they can convert grass, which we cannot eat, into nutritious food (meat and milk) for our nourishment. This microbial fermentation occurs in a digestive system which is free of oxygen where grass and other feeds are fermented to organic acids that cattle can use like it was sugar. But this process also generates methane in the digestive system. This methane is detrimental to both production, as it represents energy that could have been used for growth, and the environment -because it is released into the atmosphere as a Greenhouse Gas. If we could reduce methane generation by improving feeding efficiency in cattle production, we would simultaneously improve profits while reducing greenhouse gas emissions. Boveta can.
Genetic advancements in the growth potential of cattle today have resulted in beef diets often being deficient in the amino acids required by the animal. That amino acid deficiency results in cattle overconsuming energy (feed) which reduces the efficiency of feed conversion and increases feed costs. Our research on commercial diets led us to conclude that balancing for amino acid requirements could improve feed efficiency. Through our research efforts Boveta Nutrition has developed unique equations in an improved feeding model that allow us to formulate diets for beef cattle that do in fact more preciely meet the animal’s amino acid requirements. When diets are balanced in this fashion feeding efficiency improves, often by 10% or more. Same gain, less feed.
Reduced feed consumption and better feed conversion efficiency reduces cost and improves profits. Reduced feed intake also reduces methane production. But how much? And are there any other effects from our diet adjustment on methane production? We asked the question: when we change the diet to meet the amino acid requirements of the calf (by altering the protein ingredients in the diet) what actual impact is there on methane production?
To answer this question fermentation as would occur in the rumen was simulated in vitro in the lab. This allowed us to make precise quantitative measurements of methane from diets typically fed to feedlot calves. Methane production was then also measured from the typical diet that had its protein ingredients (soybean meal, cottonseed meal, dried distillers’ grains) altered per our model to match the amino acid requirement of the animal. The objective of this study was to measure if methane production was different or altered in the diet with its protein altered compared to the typical diet. Our hypothesis was that methane production (moles of methane per gram of diet fermented) would not be different- just less due to less intake.
When the two diets were fed to the fermenters our hypothesis was proven correct. Methane production was not different between diets because the fermentable starch was similar between the diets and peptide-nitrogen and ammonia met or exceeded microbe requirements in both diets. Therefore, any differences in total methane production between a typical feedlot diet and a feedlot diet with protein altered to meet actual amino acid requirements using our diet formulation equations would only be the result of the different amount of feed consumed. This means if feed efficiency is improved by 10% then methane (greenhouse gas) production and release into the environment will be reduced by 10% as well. Simply put- less in, less out. And that is not all.
In addition, roughage in beef diets contributes significantly to methane production. High-grain diets are typically fed to cattle in the feedlot. These diets include forage (roughage) at 6 to 10% of the diet to prevent digestive diseases, most notably acidosis. Acidosis occurs when cattle fed high grain (starch) diets produce organic acids in the rumen from fermentation at high levels. Ruminal tissue is compromised/damaged, and bacteria are then able to travel from the rumen to the liver causing further damage. Roughage inclusion in diets helps prevent acidosis.
But it is not the only way. Acidosis is also prevented when diets are balanced to meet the amino acid requirements of calves, primarily due to alleviating overconsumption of fermentable starch. Since consumption of starch is reduced by balancing for amino acid requirement, the need for roughage inclusion into diets is no longer necessary to maintain rumen health and prevent acidosis. In short, our diet formulation equations enable roughage to be pulled from beef feedlot diets.
So, we asked the question: When we properly balance a diet and remove roughage how much can we further reduce methane production? If roughage in the diet is removed, methanogenic bacterial populations would be expected to decrease and, subsequently, methane production per gram of diet organic matter fermented would be reduced. Therefore, we know that no roughage diets would have lower methane production than diets with roughage. But how much?
To determine the quantifiable effect of roughage removal from diets on methane production, our balanced no roughage diets were fed to fermenters simulating rumen fermentation as discussed above. Compared to fermenters fed a typical feedlot diet, methane production was reduced 24% when fermenters were fed the no roughage diet. This is in addition to the efficiency reduction noted above. Feed yard wet waste would also be reduced.
The Bottom Line
Reducing intake by use of Boveta’s patent pending diet formulation model improves income over feed costs by 8-12% while similarly reducing methane and wet waste. Combining that improved efficiency with reduced roughage intake provides a healthy, practical way to further improve profits and reduce methane emissions up to 30% or more.
Providing environmental stewardship while also improving production and profit for the beef industry.
Table 1. Effect of Balancing Diets to Meet Amino Acid Requirement and Roughage Removal on Ammonia and Methane Production from a Rumen Fermentation of Starch-Based Diets
|Item||Control Diet||AA Balanced with Roughage||AA Balanced with no roughage||AA Balanced with no roughage fed at 80% Intake|
|Acetic Acid (mol%)||28.3||28.4||30.0||28.5|
|Propionic Acid (mol%)||47.6||47.0||47.2||46.0|
|Isobutyric Acid (mol%)||1.3||1.1||0.9||1.1|
|Butyric Acid (mol%)||11.5||13.4||11.4||14.5|
|Isovaleric Acid (mol%)||5.6||4.9||4.9||4.6|
|Valeric Acid (mol%)||5.7||5.2||5.6||5.4|
|Total VFA (mM)||54.3||60.2||61.5||45.7|
|Total Gas (mL over 24 h)||91.1||105.3||90.8||64.6|
|Methane (mL over 24 h)||8.8||8.7||6.6||6.5|
Balancing diets with roughages, typical of feedlot diets, for the amino acid requirements of a growing calf did not alter methane production per unit of feed (dry matter consumed). Rather, methane production would be primarily reduced by lowered feed intake (8-12%) due to our AA balanced diet.
However, when roughage was removed methane production was reduced approximately 24%. Combined with an improvement in feeding efficiency of 10 to 12% (reduced intake) there is the potential for a 30 to 40% reduction in methane in ruminant animals. Further reductions could be obtained by selection of naturally efficient animals based on performance metrics.